The present invention relates to treating material and more specifically to a method and apparatus for processing high sulfur and high alkali kiln dust.
Material treating systems such as a cement material treating system results in the generation of tremendous amounts of gaseous material and dust particles which must be controlled in some manner. This gaseous material and dust cannot be allowed to escape to the atmosphere as it creates an environmental problem which is not tolerable in our present society. The physical operation of collecting the relative fine dust also presents problems. Also, once the dust is collected, disposal of the collected dust presents the additional problem of disposal. A solution for the dust problem is to cycle the dust back through an improved grate kiln system to utilize the dust for improving the abrasion resistance of the pellets. This is feasible by collecting the dust carried by the off-gas from a kiln system and dusting the pellets forming in the pelletizer or blending the dust with the raw material. Another solution for the gas and dust problem is to convert the undesirable gaseous material to a solid state dust form and remove the dust from the system.
A general object of the present invention is to provide a method and apparatus to process material having a high sulfur content which may include a high alkali content.
Still another object of the invention is to provide a method and apparatus wherein waste kiln dust may be utilized to increase the abrasive resistance of pellets processed through the treating system.
Yet another object of the present invention is to provide a method and apparatus for utilizing kiln dust as an additive to or during the agglomeration without adding ingredients to the dust to produce a more highly abrasion resistant pellet.
A further object of the present invention is to provide a method for reacting high sulfur content kiln off-gases with lime to form gypsum anhydrite which is readily collected and has the potential to be utilized as a by-product.